ISON's five-million-year journey from far reaches of solar system has apparently ended in a one-way trip around sun

Scientists say the comet ISON's five-million-year journey from the far reaches of the solar system has apparently ended in a one-way trip around the sun.

Astronomers say ISON and its long, bright tail passed just 1.2 million kilometers from the surface of the sun at 1837 UTC on Thursday. A fleet of solar telescopes found no trace of the comet emerging from the other side.

At its closest point, ISON - traveling at 350 kilometers per second - encountered temperatures estimated at 2,700 degrees Celsius. Scientists say those temperatures were hot enough to vaporize ices in the comet's body, as well as its dust and rock.

An astrophysicist tracking ISON from the U.S. Naval Research laboratory in Washington told NASA television he saw nothing coming from behind the solar disc.

Amateur Russian astronomers last year discovered ISON when it was still beyond the planet Jupiter. The discovery tantalized scientists and star-gazers across the globe with the prospects of a spectacular naked-eye light show in the skies above Earth beginning late next month.

ISON is thought to have contained frozen debris from the formation of the solar system some 4.5 billion years ago. Scientists say the comet was preserved in what is known as the Oort cloud, halfway to the nearest star from the sun.